Question about directx9 redist

Hi umm I am having a problem installing dxwebsetup coz it keeps telling me a cabinet file cannot be trusted so I gave up fixing the error and download directx9 redist instead coz it doesnt give me any errors but when dx9 redist has been installed the dolphin "missing dx9 plugin" errors are still there. Is the only way to fix these errors is to download dxwebsetup? If so, then my hope of playing brawl on my computer is lost .